Diffuser for fluid fuel burners



July 5, 1938. F. HILL 2,122,688

DIFFUSER FOR FLUID FUEL BURNERS Filed 001;. 1'7. 1956 INVENTOR. FRED ff/LL ATTORNEY Patented-Filly 193s I Z,"1ZZ;68.8

UNITED STATES PATENT OFFICE I 2,122,688 ni -roses I-o'n FLUID FUEL BUaNEns mo mu, sen Francisco, Calif. 7 Application October 17, 1936, Serial No. 106,140.

' 1.0mm (Cl. 158-15) This invention relates" to diffusers for fluid manufacture, and to otherwise generally imfuel burners and has particular reference to improve upon known diffuser devices for fluid fuel provements in structural features of such difburners. fusers. These diffusers are also variously called With the foregoing and other objects in view,

deflectors, diffusers, smelds'orjcones, and their all of which will be more apparent as this de- 5 purpose is to control the spread of flame at the scription proceeds, the invention is exemplified discharge orifice of a fluid fuel burner so that in one form in the novel construction hereinthe flame will be directed to a point in the' furafter described, illustrated in the accompanying nace where the heat will be mostefiedtlvely emdrawing, and pointed out in the claims hereto ployed. In order that sufficient volumeof airappended, it being understood that various 10 may enter the shield or diffuser to support'comchanges in the form, proportion, size and details bustion at the burner nozzle,'oriflces are proof construction of the apparatus may be revidedin the diffuser or'shield. Conicafly shaped' sorted to within the scope of the appended diffusers are well-known in this art, but they claims without departing from the spirit or sachave had several principal shortcomings. Fir'strificing any of the advantages of the invention. 15

ly, that the fuel is projected too great a distance i To moreclearly comprehend the invention, into the combustion chamber of the furnace be-' reference is directed to the accompanying drawforeit spreads to the furnace walls, and secing whereinz' ondly, lack of sufficient-supply of air tosup; Fig. 1 is a longitudinal vertical section of the port adequate combustion within the diffuser invention mounted at a furnace opening or 20 has prevented the most eflicient utilization of throat through which fuel is fed to the comheat in the furnace; thirdly, due to egp'ansion bustionchamber. and contraction'of'the diffuser walls under acv Fig. 2 is a rear view of the invention taken tual operating service, the walls oi'the diffuser from the right in Fig. 3.

crack'and break after a very short period of use. Fig. 3 is a longitudinal vertical transverse sec- This invention may be employed with either the tion on line III-III of Fig. '2. I l rotating type of oil'bumer or the non-rotating .Fig. 4 is a longitudinal vertical section of a type wherein the liquid fuel under pressure is modified form f e' v ionf v atomized at somepoint in its line of There- 5 1S il y S e t of the modfore, it is to be understood that the invention ifled form of the invention shown in Fig. en- 3 is not limited to a, particular type'o'f fluid fuel larged to show detail. of structure of slots in thei burner, but that the burner herelmdescribed and" adapter body,'the view being from the outside. illustrated is for illustrative purposes by way-of. Referring to the raw ng in which like char- 1 example of one form of use of the invention." acters of reference indicate corresponding parts I have found by actual experiment and de'min -the several views, to indicates generally a onstration that a, diffuser is morejeflicient'and burner housing of a suitabletype'of furnace in; lasts for a considerably longer of time ,which illsthe combustion chamberand l2 in-v without "cracking or breaking under; actual opdicates the f nace p n g' r hroat. Suit-.

erating'serviceconditions if the 'wall thereof is able doors l3 may be provided at the burner'n l formed in the general shape of a bell, the wall housing for purposes of furnishing draft,.the 4 of which'in-longitudinal section has a compound opening of the doorsbeingadjustable' by a rack or ogee curve.

bar HL -Asuitable burner member 'I5'of any The objects of this invention are to provide acceptable design xtendsthrough an opening" an'improved diffuser for fluid fuel burners which it in the forward wall of the burner housing will direct a ilame from a'burner tip to the point i0. For purposes of illustrating one ex'ar'ripleiof 4,5 of greatest combustion value in afurnace; touse of' 'the' invention, th'e'burner' member 15 is .1 provide adiffuser for fluid fuel' burners which shown as an ordinary pressure ,burn er ha vin g a will be maintained at relatively low temperature nozzle I6, an, atomizer I7. and a j hood, i8 sur- 7 adjacent the nozzle of the burner;- to' provide 'roun'cling the nozzle" tip. to prevent draft from, f in a burner for fluid fuel, a diffuser for acdirectly striking the discharge orifice of the non- 50, complishing the foregoing objects and which zle 5. The burner member, as illustrated, ex will also cause the atomized fuel to whirl as it tends longitudinally through an air conduit l9,

leaves the bu er o e; o Provide a d f u e which removably mounts the diffuser 20, adjafor fluid fuel burners which is efllcient in opercent the discharge end of the burner. The dif-' ation, simple in structure and economical to fuser 28 comprises a hollow body, the inner face 55 draft doors II to enter 0 of the diffuser relatively of which is substantially concentric relative to the longitudinal axis of the diffuser; but has progressively increasing diameters from the burner-receiving portion to the oppositeend of the diffuser, so that the wall of the diffuser in transverse section through the longitudinal axis of the diffuser is delineated by a compound curve which is concave at the portion 2i adjacent the mouth 22, which would correspond to the sound bow of a bell, the concavity of the curve flattening out at 28 and fading into a convex curve 24 at the portion adjacent the burner and'which would correspond to the shoulder of a bell, the radius of the rearward portion of the body which is most near- 1 the diffuser is'provided 2 1y radial to the collar 28, with a plurality of circumferentially arranged and relatively spaced openings 21. These openings 21 comprise aplurality of elongated slots having their side edges corresponding with the outer and inner faces of the diffuser body' and preferably have their end walls 28 substantially parallel with the axis thereof. This arrangement of the openings 2'! permits air from the cient to adequately support combustion is supplied within the difl'user. The draft of air thus entering the diffuser also serves to keep the wall cool closely adjacent the burner so that the life of the diffuser is prolonged. As the air entering openings 21 mixes with the atomized fuel it naturally becomes rap-' idly and intensely heated so that it expands as it reaches the mouth 22 of the diffuser and thus it carries the flame along the outwardly-flaring wall adjacent the mouth 22 of the difl'use until the flame reaches the edge of the mouth. At the mouth 22 the diffuser is in spaced relation to the throat l2 of the furnace as at 29. Through this space 29 additional air from the draft door it picks up the flame and carries it into the furnace combustion chamber i I, but the air entering through the slots 21 having expanded due to the heat, the flame expands immediately upon entering the combustion chamber of the furnace, instead of'being projected a considerable distance into the combustion chamber before it expands. This increases the temperature of the combustion chamber at the feed end and'there-v by makes the fuel more emcientand reduces the total-fuel cost.

In the modification of Fig. 4. the elongated slots 21. are radial to the longitudinal axis of the diffuser on the inner face thereof, but the side walls 2'!- of the slots are angularly inclined substantially 45 laterally to the inner face of the diffuser so that the opening in the outer wall is offset from the opening in the inner wall. By such arrangement of the slots 21 the inrushing draft tends to whirl the flame within the diffuser. I

arc of the concave curve being greater than the radius of the be readily replaced,

- radius of the arc of Thedirectionoftravel oftheflameisindicated by the dotted lines 3. in Pig. 1.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States is:

2. A'difluser for fluid fuel burners comprisportion adjacent the said .one end of the diffuser body is concave and the portion adjacent the burner receiving opening is convex, the radius of the arc of the concavely curved portion being greater than the radius of the arc of the convexedly curved portion,

said body'having a plurality of relatively spaced-openings adjacent the burner receiving opening.

' 3. A diffuser for fluid fuel burners comprising hollow body open at one end and having the inner face of the body wall tapered inwardly from the said one end toward its opposite end through the axis of the diffuser having its inner face delineated by'a compound cur-vein which the portion adjacent the said one end" of the diffuser body is r the concavely, curved portion being greater than the radius of the arc of the convexedly curved portion, said bodyhaving a plurality of circumferentially arranged relatively spaced openings adjacent the burner receiving opening, the side walls within said openings being inclined at an angle to the radius of the body.

concave and the portion adjacent the burner receiving opening is convex, the radius of .the arc of the concavely curved portion being than the. radius curved portion.

the said one end of the diffuser- 

